Import Resources into Terraform

Import existing AWS resources into Terraform state. Arguments: $ARGUMENTS

When to Use Import

• Bringing existing resources under Terraform management
• Recovering from accidental state deletion
• Migrating from other IaC tools
• Adopting Terraform for existing infrastructure

Import Process

1. Write Resource Configuration

Before importing, you must have the resource defined in Terraform:

# This must exist BEFORE import
resource "aws_instance" "web" {
  # Configuration will be filled after import
}

2. Run Import Command

# Terraform
terraform import <resource_address> <resource_id>

# OpenTofu
tofu import <resource_address> <resource_id>

3. Fill in Configuration

After import, update the resource to match actual state.

Common Import Commands

EC2 Instance

terraform import aws_instance.web i-1234567890abcdef0

Security Group

terraform import aws_security_group.web sg-1234567890abcdef0

S3 Bucket

terraform import aws_s3_bucket.data my-bucket-name

IAM Role

terraform import aws_iam_role.app my-role-name

RDS Instance

terraform import aws_db_instance.main my-database-id

VPC

terraform import aws_vpc.main vpc-1234567890abcdef0

Subnet

terraform import aws_subnet.private subnet-1234567890abcdef0

EKS Cluster

terraform import aws_eks_cluster.main my-cluster-name

EKS Node Group

terraform import aws_eks_node_group.main my-cluster:my-node-group

Import Block (Terraform 1.5+)

Use import blocks for declarative imports:

# imports.tf
import {
  to = aws_instance.web
  id = "i-1234567890abcdef0"
}

import {
  to = aws_security_group.web
  id = "sg-1234567890abcdef0"
}

Then run:

terraform plan -generate-config-out=generated.tf

Output Format

## Import Resource: [Resource Type]

### Resource Details
- **Address**: aws_instance.web
- **ID**: i-1234567890abcdef0
- **Type**: aws_instance

### Pre-Import Checklist
- [ ] Resource configuration exists in .tf files
- [ ] Resource ID verified in AWS console
- [ ] No conflicting resource in state
- [ ] Backup of current state exists

### Import Command
```bash
terraform import aws_instance.web i-1234567890abcdef0

Import Result

aws_instance.web: Importing from ID "i-1234567890abcdef0"...
aws_instance.web: Import prepared!
  Prepared aws_instance for import
aws_instance.web: Refreshing state...

Import successful!

The resources that were imported are shown above. These resources are now in
your Terraform state and will henceforth be managed by Terraform.

Post-Import Steps

1. View imported state

   terraform state show aws_instance.web
   

2. Update configuration to match

   resource "aws_instance" "web" {
     ami           = "ami-0abcdef1234567890"
     instance_type = "t3.large"
   
     vpc_security_group_ids = [aws_security_group.web.id]
     subnet_id              = aws_subnet.private.id
   
     tags = {
       Name = "myproject-prod-web"
     }
   }
   

3. Verify no changes

   terraform plan
   # Should show: No changes. Infrastructure is up-to-date.
   

Configuration Template

Based on the imported resource, here's a configuration template:

resource "aws_instance" "web" {
  ami                    = "ami-0abcdef1234567890"  # From state
  instance_type          = "t3.large"               # From state
  subnet_id              = "subnet-xxx"             # Replace with reference
  vpc_security_group_ids = ["sg-xxx"]               # Replace with reference

  root_block_device {
    volume_size = 100
    volume_type = "gp3"
  }

  tags = {
    Name        = "myproject-prod-web"
    Project     = var.project
    Environment = var.environment
    Terraform   = "true"
  }
}

Common Issues

Issue	Cause	Solution
Resource already in state	Duplicate import	Remove first: terraform state rm
Cannot find resource	Wrong ID	Verify ID in AWS console
Configuration mismatch	Missing attributes	Add required attributes to config

## Workflow

1. Verify resource exists in AWS
2. Get resource ID from AWS console
3. Write minimal resource configuration
4. Run import command
5. View imported state
6. Update configuration to match state
7. Run plan to verify no changes
8. Add proper references and variables